Ethyl Hexyl Acetate Research Articles

Reactive Chromatography for the Synthesis of 2-Ethylhexyl Acetate

Reactive chromatography (RC) combines reaction and chromatography in a single unit. Due to simultaneous separation of products it can be advantageously used for reversible reactions to obtain the enhanced performance. It is a promising alternative to reactive distillation when the components are temperature sensitive and less volatile. In the present work, we study the application of RC for the synthesis of 2-ethylhexyl acetate through esterification of acetic acid with 2-ethylhexanol. Amberlyst-15 has been used as a catalyst/adsorbent. Several aspects such as reaction kinetics, multicomponent adsorption equilibria, and reaction-separation study using fixed bed chromatographic reactor are covered. The kinetics was studied in a stirred batch reactor. The effects of various parameters such as speed of agitation, particle size, temperature, mole ratio of reactants, and catalyst loading have been investigated. Kinetic modeling was performed using modified activity based Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. Non-reactive binary adsorption experiments were performed to determine the parameters of Langmuir adsorption isotherm by minimizing the errors between the experimental and predicted breakthrough curves. Further, the reactive chromatography experiments were performed to obtain the reactive breakthrough curves which indicate a clear potential for the use of reactive chromatography for this reaction. The obtained data has been compared with the predictions of mathematical model of the chromatographic reactor.

Biological Activity and Composition of the Essential Oil of Tetrataenium Nephrophyllum (Apiaceae) from Iran

The aerial parts of Tetrataenium nephrophyllum were collected at the flowering stage, hydrodistilled, and the essential oil was analyzed by GC and GC-MS. Forty components accounting for 97.9% of the total oil were identified. Germacrene D (38.5%), 2-ethylhexyl acetate (11.2%), n-octyl 2-methylbutanoate (9.2%) and geranyl isovalerate (8.3%) were the major constituents. Sesquiterpene hydrocarbons (51.3%) and aliphatic esters (40.4%) were found to be the main group of compounds. The antimicrobial activity of the essential oil of T. nephrophyllum was determined against seven Gram-positive and Gram-negative bacteria (Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, S. epidermidis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae), as well as three fungi (Candida albicans, Saccharomyces cerevisiae and Aspergillus niger). The bioassay showed that the oil exhibited moderate to high antimicrobial activity.

Liquid-surface immobilization system and liquid–liquid interface bioreactor: Application to fungal hydrolysis

Novel fungal cultivation and bioconversion systems are proposed. Spores and mycelia of a fungus suspended in a liquid medium were effectively floated on a liquid surface by the aid of a ballooned microsphere (MS). Many fungi such as Aspergillus and Penicillium formed a thick and physically strong fungus-MS mat on the liquid surface followed by stationary cultivation (LSI). The fungus-MS mat of Absidia coerulea IFO 4423 was overlaid by a solution of 2-ethylhexyl acetate ( 1) in n-decane (liquid–liquid interface bioreactor, L-L IBR). The strain could efficiently catalyze the hydrolysis of 1 to 2-ethyl-1-hexanol ( 2). The accumulation of 2 in the L-L IBR was significantly higher than those in emulsion and organic-aqueous two-liquid-phase systems and a formerly reported interface bioreactor (solid–liquid interface bioreactor, S-L IBR). Furthermore, lipase production in the LSI system was also higher than that in a submerged cultivation system.

Adhesion performance of UV-cured semi-IPN structure acrylic pressure sensitive adhesives

UV-curable solvent-free pressure sensitive adhesives (PSAs) are gaining importance in the area of adhesives because of increasing environmental concerns and the goal to reduce volatile organic compounds (VOCs) in work areas and consumption places. These PSAs have advantages such as low emission of VOCs, a solvent-free process, a fast producton rate at ambient temperature and only a modest requirement for operating space. In this study, UV-curable PSAs were investigated by measuring their adhesion performance in terms of probe tack, peel strength, shear adhesion failure temperature (SAFT) and holding power. PSAs were synthesized from 2-ethylhexyl acrylate (2-EHA), acrylic acid (AA) and vinyl acetate (VAc), using variations in AA concentration to control the glass transition temperature (T g) of the prepared PSAs. In addition, two types of trifunctional monomers, trimethylolpropane triacrylate (TMPTA) and trimethylolpropane ethoxylated (6) triacrylate (TMPEOTA), which have different chain lengths, were used to form semi-interpenetrating polymer network (semi-IPN) structures after UV exposure. With increasing AA concentration in the PSAs, both the T g and viscosity increased. Also, probe tack and SAFT increased, but peel strength decreased. After UV irradiation, probe tack decreased, and SAFT and peel strength increased as AA concentration increased in the PSAs. In most cases, cohesive failure changed to interfacial failure after UV exposure. Also, TMPTA increased the cohesion of PSAs; however, TMPEOTA affected the mobility of PSAs due to the different chain lengths of the two types of trifunctional monomer in a different way. The increase of TMPEOTA content diminished the cohesion of PSAs. Consequently, the adhesion performance of the PSAs was closely related to the T g of the PSAs, and the two types of trifunctional monomer showed different adhesion performances.

Adsorption of polyethylene from thermodynamically good solvents on a zeolite stationary phase

AbstractAdsorption of linear polyethylene and isotactic polypropylene on columns packed with zeolites ZSM‐5, Y, and silicalite was studied using high‐temperature liquid phase chromatography. Linear polyethylene was fully retained on a column packed with ZSM‐5 zeolite from non‐polar solvents, such as 1,1,2,2‐tetrachloroethane and 1,3,5‐trimethylbenzene at a temperature of 140°C. Partial adsorption on ZSM‐5 zeolite was found for polyethylene in 1,2,4‐trichlorobenzene and on silicalite from 1,2,4‐trichlorobenzene and 1,3,5‐trimethylbenzene. On the other hand, adsorption of polyethylene was not found from polar liquids, such as 2‐ethylhexyl acetate, cyclohexyl acetate, and cyclohexanone. Isotactic polypropylene was not adsorbed on any tested sorbent.

Acrylate‐based pressure sensitive adhesive in fabrication of transdermal therapeutic system

AbstractAn acrylate‐based pressure sensitive adhesive (PSA) was synthesized to incorporate in a design of a drug‐in‐adhesive (DIA) type transdermal therapeutic system (TTS) for nitrendipine and nicorandil in treatment of hypertension and angina pectoris, respectively. Solutions of 2‐ethylhexyl acrylate (EHA; 85% w/w), methyl methacrylate (MMA; 10% w/w), acrylic acid (AA; 3% w/w) and vinyl acetate (VA; 2% w/w) in either ethyl acetate, acetone or methanol were polymerized under free radical conditions to synthesize the PSA. The effects of solvent, reaction time, initiator concentration and reaction temperature on polymerization were studied. The resultant copolymers were characterized by 1H‐NMR, IR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) and the intrinsic viscosities, refractive index, peel strength, moisture uptake and skin irritation potential were determined. The PSA was used to develop DIA type patches for delivery of nitrendipine and nicorandil. The TTS were evaluated for thickness, weight, peel strength, moisture uptake, in vitro release and in vitro skin permeation through guinea‐pig skin. The copolymer found to effectively control the rate of drug release and the corresponding TTSs could be successfully employed in transdermal delivery of nitrendipine and nicorandil. Copyright © 2003 John Wiley & Sons, Ltd.

Properties of pressure sensitive adhesive made of acrylic quaternary copolymers and their blends with vinyl chloride copolymers

Acrylic quaternary copolymers (AQC) were synthesized from copolymerization reaction of 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA), ethyl acrylate (EA) and vinyl acetate (VAc). The blends of AQC with poly(vinyl chloride-co-vinyl acetate) (PVC-VAc) and with poly(vinyl chloride-co-vinyl propionate) (PVCVP) were prepared by solution blending. Pressure sensitive adhesive (PSA) properties of AQC and their blends were investigated. Glass transition temperature Tg and holding power of AQC decreases with increasing contents of 2-EHA and BA. Tackiness, however, increases with increasing the contents of 2-EHA and BA. Peel strength shows maximum value for the sample with 15 wt% of those monomers. Tackiness of blend systems is similar, but holding power begins to decrease at 15 wt% or higher PVCVAc contents in AQC+PVCVAc blends. On the other hand, holding power of AQC+PVCVP blends increases as the contents of PVCVP increases. Failure modes of the blend are adhesive except for blends with 5 wt% of PVCVP.

Formulation Optimization and Stability Study of Transdermal Therapeutic System of Nicorandil

The aim of this research investigation was to fabricate acrylate-based stable transdermal therapeutic system (TTS) of nicorandil, which could deliver drug through transdermal route. Monolithic TTS was fabricated in pressure sensitive adhesives (PSAs)—(a) terpolymer (PSA1) of 2-ethylhexyl acrylate, methyl methacrylate, and acrylic acid, (b) copolymer (PSA2) of 2-ethylhexyl acrylate, methyl methacrylate, acrylic acid, and vinyl acetate, and (c) Eudragit E100® pressure sensitive adhesive (PSA3). To enhance the flux of nicorandil, skin permeation enhancer N-methyl-2-pyrrolidone (NMP) was investigated at different concentrations (0.05–5%) in PSAs. Fabricated TTS was evaluated for in-vitro release and skin permeation through guinea pig skin. Maximum flux of nicorandil was observed from Eudragit E100 based TTS and kept for stability study at refrigeration, 25°C/30% RH and 30°C/60% RH. Patches were evaluated for various physicochemical parameters. Formulation was observed to be relatively more stable at refrigeration. Shelf life of the formulation was found to be 270, 270, and 30 days at refrigeration, 25°C/30% RH and 30°C/60% RH conditions, respectively. Nicorandil could be successfully derived from Eudragit E100 based TTS, but attention needs to be given to improve its chemical stability in formulation.

Measurements of Density and Viscosity of Binary Mixtures of Several Flavor Compounds with 1-Butanol and 1-Pentanol at 293.15 K, 303.15 K, 313.15 K, and 323.15 K

Density and viscosity for binary mixtures of four flavor compounds (benzyl acetate, 2-ethylhexyl acetate, benzaldehyde, and pentyl acetate) with 1-butanol and 1-pentanol over the whole composition range have been measured at four different temperatures (293.15, 303.15, 313.15, and 323.15 K) and atmospheric pressure. The excess molar volume (VE) and viscosity deviations (ΔηL) were calculated and fitted to a Redlich−Kister type polynomial relation.

EXTRACTION OF Am(lll) AND Eu(lll) NITRATES BY 2-6-DI-(5,6-DIPROPYL-1,2,4-TRIAZIN-3-YL)PYRIDINES 1

ABSTRACT The extraction of Am(lll) and Eu(lll) by 2,6-di(5,6-dipropyl-1,2,4-triazin-3-yl)-pyridines from mostly 1·9 M (HNO3 + NH4NO3) was studied. The compound with n-propyl (DPTP) forms dimers and trimers in mixed branched alkanes modified with 2-ethyl-1-hexanol. The self-association is supported by enhancing the HNO3 concentration from 0·3 to 0·9 M. In the above modified diluent, DPTP extracts Am(lll) and Eu(lll) nitrates as the complexes Am(NO3)3HNO3-3B and Eu(NO3)3HN033B. The Am(lll)/Eu(lll) separation factor is typically 100 -120. The extraction and separation efficiency of DPTP strongly decreases in the order of diluents (each modified with 2-ethyl-1-hexanol) branched alkanes > cyclohexane > 2-methyl-4-pentanone > 2-ethylhexyl acetate > benzene > chlorobenzene > xylene. 1-Octanol and 2-ethyl-1-hexanol modifiers support appropriately the solubility of protonated forms of DPTP in branched alkanes, and moderately enhance the extraction of Am(lll) and Eu(lll). 1-Butanol modifier allows a higher extraction efficiency but supports less the solubility. The optimum extraction and separation efficiency is attained at 10 - 20 vol% modifier. The isopropyl analogue extracts Am(lll) more effectively than DPTP, but the extraction is slow and the separation from Eu(lll) is inefficient.

Interface bioreactor packed with synthetic polymer pad: Application to hydrolysis of neat 2-ethylhexyl acetate

A new practical carrier for an interface bioreactor has been developed. This carrier consists of two different crosslinks, i.e., polyvinyl alcohol (PVA)-glutaraldehyde (GA) and alginate (ALG)-Ca 2+ crosslinks. This combined crosslinking leads to high gel strength, heat tolerance, and water holding capacity. A pad-packed interface bioreactor using the crosslinked gel pads was applied to the hydrolysis of 2-ethylhexyl acetate using Candida cylindracea ATCC 14830. The pad-packed interface bioreactor with the crosslinked gel pads gave satisfactory accumulation of 2-ethyl-1-hexanol compared to that with agar pads.

Microencapsulation of pheromone-analogue and measurement of the sustained release

A model study was conducted to establish 2 feasible production and application systems for the long-term, sustained release of pheromone into the atmosphere of targeted areas. The desired goal of effective release was set at least half a year. 2-Ethylhexyl acetate (EHA) was selected as a pheromone analogue due to its similar structure and easier access for quantitative analysis. At first EHA was impregnated in wax particles, which were then encapsulated employing the complex coacervation of a gelatin-gum arabic system. The release period of EHA through the gelatin wall, however, turned out to be too short--only a week at most. As a second attempt, a modification of the two-phase emulsion technique was employed to encapsulate multiple numbers of wax particles in hydrated networks of gelatin. Though the initial release rate of EHA was still too high, 60 per cent of encapsulated EHA underwent sustained release over six months after absorbed moisture had completely evaporated. A two-step mechanism of mass transfer was proposed and the related parameters in terms of the capacity coefficient and effective diffusion coefficient were estimated.

Preconcentration by dithiocarbamate extraction for determination of trace elements in natural waters by inductively-coupled plasma atomic emission spectrometry

Preconcentration by dithiocarbamate extraction into 2-ethylhexyl acetate for simultaneous determination of trace elements in natural water is described. After 250-fold concentration, the organic phase is used directly for inductively-coupled plasma atomic emission spectrometry. Thirteen elements (As, Se, Mo, Zn, Cd, Ni, Co, Sn, Fe, Cr(VI), Pb, V and Cu) are simultaneously concentrated at pH 4.3 with the combination of ammonium tetramethylenedithiocarbamate and dibenzylammonium dibenzyldithiocarbamate and are determined in the extract; Mn and Cr(III) are also determined after preconcentration at pH 6.9 with the same chelating agents. Lake waters are analyzed by this method.

Computer optimization of the formulation of acrylic plaster.

A computer optimization technique was applied to obtain the optimum formula of acrylic plaster vehicle containing ketoprofen (KPF). The dissolution rate of KPF, in vivo percutaneous absorption of KPF, stability of the dissolution behavior of KPF and adhesiveness of the plaster were determined as characteristics for deciding the formula of an optimum plaster vehicle. The amounts of 2-ethylhexyl acrylate (X1), vinyl acetate (X2) and 2-hydroxyethyl acrylate (X3) were selected as factors (independent variables). The plaster characteristics were predicted by the secondorder polynominal regression equation involving these factors. The physical meaning of the regression equation for each characteristic was defined by the application of contour graphs. A mixture of 65 g of X1, 60 g of X2 and 1.38 g of X3 was predicted to be the optimum for the plaster vehicle.

2-Ethylhexyl acetate

2-Ethylhexyl acetate